The invention relates to methods and apparatus for optical switches and optical communication.
Optical switches are widely used in the fiber optical communication industry. Typically, optical switches operate as network protection switches or elements of optical add/drop systems. As transmission bands, switching speeds, and traffic capacities increase, communication systems demand smaller, cheaper, and better devices and switches.
Conventional optical switches used for network protection are mostly mechanical switches, which contribute significant bulk due to the design configuration. Conventional switches normally employ a rotating mirror or rotating slice in the optical path to steer the beam in different directions to perform the switching function. Due to the large size and rotation of the mirror, the switch normally requires a collimator for each optical port (input and output) to extend the optical path to put rotation mirrors and other switching mechanisms into the optical path to block or switch the optical beams. The cost to build each individual switch module is difficult to reduce due to the many components employed, such as the collimators.
Optical communication systems also generally employ other components, such as optical add/drop multiplexers (OADM). These systems require compact switches, ideally integrated into a small switch array. Conventional switches, however, are typically produced using MEMS technology, which is very expensive. Further, MEMS switches are difficult to equip with a latching mechanism to maintain the status of the switch when power is terminated. In addition, MEMS switches typically have moving parts subject to wear and often require high voltage to control the switch, both of which tend to reduce reliability.
A method and apparatus for communications according to various aspects of the present invention comprises a switching system configured to receive optical signals and direct the optical signals along a selected optical path. The switching system suitably includes more than one switch, and at least one of the switches may include a variable refractive material having a first state and a second state, wherein the optical signal is transmitted via a first path when the variable refractive material is in the first state and the individual channel signal is transmitted via a second path when the variable refractive material is in the second state. The switching system may alternatively or additionally include a switch element having a reflective state and a transmissive state, wherein the optical signal is reflected via a first path when the switch element is in the reflective state and the individual channel signal is transmitted via a second path when the switch element is in the transmissive state.